A great number of airplanes use the world's airspace to travel between locations. Many people use or prefer to travel by airplanes because of the speed and convenience of air travel. To provide for the air traffic, thousands of airports have been built around the world. Both large international airports, such as Denver International Airport, and smaller regional or private airports allow the ever-growing population of air travelers to take-off and land from nearly any region in the world.
Most all airports are generally arranged in the same manner. For example, each airport includes at least one runway that allows airplanes to take-off from or land at the airport. Generally, except in the most rudimentary airports, airports also include a network of taxiways that allow airplanes to travel between the runway(s) and other parts of the airport, such as the terminal or aircraft hangers. In many small airports, the taxiways are simple to navigate and follow. However, at larger airports that handle a larger volume of air traffic, the taxiways can become a complex and intertwined network of paths among and between the parts of the airport. In situations where the taxiways are complex and/or not well marked, pilots often require a map or an electronic navigation system to navigate the taxiways.
Several organizations supply airport maps or electronic navigation systems that provide maps of taxiways and runways at an airport. One type of airport map system is the Taxi Position Awareness (TPA) application of an Electronic Flight Bag (EFB) system provided by Jeppesen Sanderson, Inc. of Englewood, Colo. The EFB is a system that provides electronic information to the pilot, such as terrain information, navigation information, or telemetry about the airplane. The TPA shows a rendered version of the airport, with the runway and taxiways displayed on a computer monitor. Generally, the TPA is a “geo-referenced” map that can use the actual coordinates or position of the airplane, usually derived from a position sensor, such as a Global Positioning System (GPS), to display the location of the airplane on the taxiways or runways at any given time. In simple terms, a geo-referenced map provides a system for locating objects on the surface of the earth according to “real world” coordinates, such as latitude and longitude. For instance, a geo-referenced map can use the latitude and longitude of an object, such as an airplane, to display the airplane on the geo-referenced map in the same position as the airplane's actual, physical position on the surface of the earth.
To create the geo-referenced map in the TPA, a map creator receives a description or other information about the airport. In one situation, the map creator may receive a very detailed map generated from a highly accurate survey of the airport. These accurate maps can then be arranged in the geo-referenced, TPA map according to clearly indicated and known geographical markers or locations, such as section markers or other typical survey points. In some situations, the map creator receives the initial airport plans, which are then converted into an electronic map using the measurements provided in the plans. Generally, to enter into service, airports must provide or publish the locations of the ends of the runways so that the precise locations of the runway ends are generally known. The TPA maps may then be located and oriented according to the locations of the runway ends. The position and orientation of the remainder of the airport map is then generally oriented to the ends of the runways.
Unfortunately, prior maps suffer from a number of inaccuracies. For instance, the documents and plans provided to the map creator are often inaccurate or out-of-date. While the busiest airports in the world often have extremely accurate airport maps, smaller regional or lesser-used airports often have slightly inaccurate or outdated maps. In some situations, the positions, orientations, designations, or dimensions of the taxiways or other parts of the airport map may be skewed or rendered incorrectly when geo-referencing the airport plans. Such inaccuracies may cause pilots to become disoriented when taxiing to and from a runway. It is with respect to these and other considerations that the present invention has been made.